1. Field of the Invention
This invention relates to a process and device for determining the alignment of a body with respect to a reference direction in which the body, particularly a roller of a printing press, is mounted for rotation around a lengthwise axis.
2. Description of Related Art
It has been suggested that a printing press be modified in order check the alignment of its rollers such that the axes or axis pieces of the rollers are provided with highly-planar end faces or provided with a high-precision adapter as an extension of the axial direction of the roller. Utilizing the end faces of the roller or the adapter attached to the roller the components of the angular alignment of the roller are determined with respect to a reference direction. This is done by means of a two-dimensionally acting angular position transducer, such as an optical gyro, which operates with high precision to determine the angular alignment of the roller with respect to a reference direction.
One problem in this approach is that it is extremely difficult to produce the end faces or the corresponding adapter with the necessary precision. That is, to achieve the required measurement accuracy, the end surfaces or the adapter must be produced with a surface quality which has a roughness measure must be much less than one micron.
A primary object of this invention is to devise a process and a device for determining the alignment of a body, which is mounted to rotate around its lengthwise axis, such that precise alignment measurements are possible even for roughly fabricated surfaces on the end faces of the body or on a surface, such as a high precision adapter, which is essentially parallel thereto.
This object is achieved by a process and a device described herein. In the process of the invention, precise determination of the alignment of a body depends neither on precisely fabricated end faces of the cylindrical body nor on a precisely fabricated adapter, since possible mis-orientation of the position measurement probe with respect to the lengthwise axis of the body can be reduced or eliminated by the evaluation of several measurement positions.
In a preferred embodiment, the position measurement probe is attached to the end face of the body or to a surface parallel to the end face of the body by means of magnetic forces.